NATIONAL RADIO ASTRONOMY OBSERVATORY RESEARCH FACILITIES for the SCIENTIFIC COMMUNITY 2021 Atacama Large Millimeter/submillimeter Array Karl G. Jansky Very Large Array Central Development Laboratory Very Long Baseline Array CONTENTS RESEARCH FACILITIES 2021 NRAO Overview . 1 Atacama Large Millimeter/submillimeter Array (ALMA) . 2 Very Long Baseline Array (VLBA) . .6 Karl G. Jansky Very Large Array (VLA) . .8 Central Development Laboratory (CDL) . .14 Student & Visitor Programs . .16 (above image) One of the five ngVLA Key Science Goals is Using Pulsars in the Galactic Center to Make a Fundamental Test of Gravity. Pulsars in the Galactic Center represent clocks moving in the space-time potential of a super-massive black hole and would enable qualitatively new tests of theories of gravity. More generally, they offer the opportunity to constrain the history of star formation, stellar dynamics, stellar evolution, and the magneto-ionic medium in the Galactic Center. The ngVLA combination of sensitivity and frequency range will enable it to probe much deeper into the likely Galactic Center pulsar population to address fundamental questions in relativity and stellar evolution. Credit: NRAO/AUI/NSF, S. Dagnello (cover) Rendering of ngVLA antennas. Credit: NRAO/AUI/NSF, S. Dagnello (back cover) ALMA map of Jupiter showing the distribution of ammonia gas below Jupiter’s cloud deck. Credit: ALMA (ESO/NAOJ/NRAO), I. de Pater et al.; NRAO/AUI NSF, S. Dagnello NRAO Overview The National Radio Astronomy ALMA photo: Pablo Carrillo Pablo ALMA photo: Observatory (NRAO) is delivering transformational scientific capabili- ties and operating three world-class telescopes that are enabling the as- tronomy community to address its highest priority science objectives. The NRAO telescope suite includes the Atacama Large Millimeter/submillimeter Array (ALMA), the Karl G. Jansky Very Large Array (VLA), and the Very Long Baseline Array (VLBA). Each is the world leader in its observing domain. Collectively, these telescopes enable scientists to observe from submillimeter to meter wavelengths with excellent resolution, sensitivity, and frequency coverage. Used individually or in combination, the NRAO telescopes provide the capabilities required to enable science for the 2020s and beyond, such as placing constraints on the nature of dark energy, imaging the first galaxies, and directly observing planet formation in proto-planetary disks. ALMA is opening new windows into the cold Universe via a major increase in sensitivity and resolution at millimeter and submillimeter wavelengths and is providing, for the first time, detailed images of stars and planets in formation, young galaxies being assembled throughout cosmic history, and much more. At the adjacent centimeter-wavelength range, the Jansky VLA has scientific capabilities that are comparable to ALMA and exceed the original VLA capabilities by one to four orders of magnitude. These Jansky VLA capabilities were delivered on schedule and on budget, and are meeting all of the project’s technical specifications and scientific objectives. The Jansky VLA is the world’s most capable and versatile centimeter-wave imaging array. The on-going Very Large Array Sky Survey (VLASS) is the highest resolution all-sky radio wavelength survey ever undertaken. The VLBA is the premier dedicated Very Long Baseline Interferometry (VLBI) array in the world. Astrometry with the VLBA has reached a precision of a few micro-arcseconds, enabling distance and proper motion measurements of astronomical objects in the solar neighborhood, across the Milky Way, within the Local Group, and into the Hubble flow. When the VLBA is used in conjunction with the phased VLA and the Green Bank Telescope, the resultant High Sensitivity Array greatly enhances VLBI sensitivity and significantly broadens the discovery space that can be addressed. To maximize the usage and science impact of the NRAO facilities, NRAO aims to broaden their access to all astronomers, through uniform and enhanced user support services. These services are coordinated Observatory-wide by the Science Support and Research Department and are provided by the North American ALMA Science Center in Charlottesville, Virginia and the Pete V. Domenici Science Operations Center for the VLA, and VLBA in Socorro, New Mexico. The NRAO is also developing forefront technology to continuously improve our facilities and to realize next generation facilities. Taking advantage of the outstanding technical expertise across NRAO, the Central Development Lab oversees a science-driven research and development program that will help realize key science goals, such as the detection of gravitational waves via pulsar timing and the study of the epoch of reionization. The community and the NRAO have initiated the design of a future large area radio telescope, a next generation VLA (ngVLA). This ngVLA will be optimized for imaging thermal emission to milli-arcsecond scales, will address a range of ambitious, high priority science goals, and will open new discovery space from protoplanetary disks to distant galaxies. After more than six decades of continual improvement, the NRAO comprises the nation’s core competency in radio astronomy, an invaluable resource for the astronomy community in the U.S. and around the world. 1 Atacama Large Millimeter/ submillimeter Array (ALMA) Altiplano de Chajnantor, Chile The Atacama Large Millimeter/submillimeter Array (ALMA) enables transformational research into the physics of the cold Universe, regions where the sky is dark in the visible part of the spectrum but shines brightly at millimeter wavelengths. ALMA can probe the origin of the first heavy elements and image interstellar gas in the process of forming new planets, thus providing a window on cosmic origins. The telescope is situated on the Chajnantor plain of the Chilean Andes at an altitude 5000 m above sea level, where the Earth’s atmosphere is largely transparent at millimeter wavelengths. ALMA provides unprecedented sensitivity and imaging fidelity in the (sub) millimeter observing window. ALMA has 66 high-precision antennas and is capable of imaging the sky at resolutions as fine as 0.005 arcsec, a factor of ten better than the Hubble Space Telescope. ALMA is the most sensitive and capable millimeter interferometer in the world. In response to the COVID-19 outbreak, ALMA science operations are currently suspended. The Call for Proposals for Cycle 8 has been delayed to March 2021 and the proposal deadline is expected in April 2021 for observations beginning in October 2021.The Call for Proposals and other documentation are available on the ALMA Science Portal (almascience.nrao.edu). Updates on ALMA’s return to operations will be posted as news items on the Science Portal. The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/ NRAO and NAOJ. ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA. The North American ALMA Science Center (NAASC) The North American ALMA Science Center, based at the NRAO headquarters in Charlottesville, Virginia, supports the use of ALMA by the North American scientific community, and conducts research and development for future ALMA upgrades. Because of the COVID-19 outbreak, visits to Charlottesville are not currently supported. However, NAASC scientific and technical staff offer remote support to assist users in processing and analyzing their ALMA data. The NAASC provides a number of additional key services, including calibrating, imaging, and distributing ALMA data, organizing and hosting conferences, training sessions, and workshops, supporting ALMA archival research, and assisting users during the preparation and submission of ALMA proposals and observations. The NAASC also prepares and maintains ALMA user documentation and web sites, and runs the ALMA Helpdesk. The NAASC is operated by NRAO in partnership with the National Research Council of Canada, Herzberg Institute of Astrophysics. Users may request assistance from the NAASC through the ALMA Helpdesk at help.almascience.org. 2 KEY SCIENCE Origins of Galaxies Origins of Chemical Complexity Origins of Planets Trace the cosmic evolution of key elements Trace the evolution from simple to complex Image protoplanetary disks in nearby (150 pc) from the first galaxies (z>10) through the organic molecules through the process of star formation regions to resolve the Earth peak of star formation (z=2–4) by detecting star and planet formation down to solar forming zone (~1 AU) in the dust continuum their cooling lines, both atomic ([CII], [OIII]) system scales (~10-100 AU) by performing at wavelengths shorter